bug in minAssGTZ() using minpoly ?

[kroeker@…]

Something is fishy with the following example:

LIB("primdec.lib");
ring rng = (3,vv),(xx,yy,zz,ww),dp;
minpoly = (vv^2+1);
ideal I = (vv)*yy-1,-xx*yy*zz+zz^2+ww;
list L1 = minAssGTZ(I);
list L2 = minAssGTZ(I,"GTZ");
list L3 = minAssGTZ(I,"facstd");
L1;
L2;
L3;

ideal I1 = std( L1[1] );
ideal I2 = std( L2[1] );
ideal I3 = std( L3[1] );

idealsEqual(I1, I2); // sometimes = 0
idealsEqual(I2, I3); // sometimes = 0

the output varies from trial to trial. Here is one snapshot:

> ring rng = (3,vv),(xx,yy,zz,ww),dp;
> minpoly = (vv^2+1);
> ideal I = (vv)*yy-1,-xx*yy*zz+zz^2+ww;
> list L1 = minAssGTZ(I);
> list L2 = minAssGTZ(I,"GTZ");
> list L3 = minAssGTZ(I,"facstd");
> L1;
[1]:
   _[1]=yy+(vv)
   _[2]=(vv)*xx*zz+zz^2+ww
> L2;
[1]:
   _[1]=yy+(vv)
   _[2]=-xx*zz+zz^2+ww
> L3;
[1]:
   _[1]=yy+(vv)
   _[2]=(vv)*xx*zz+zz^2+ww
> 
. ideal I1 = std( L1[1] );
> ideal I2 = std( L2[1] );
> ideal I3 = std( L3[1] );
> 
. idealsEqual(I1, I2); 
0
> idealsEqual(I2, I3); 
0

[hannes]

duplicate to tr. #679, fixed with 3106b37eea17482acd0b02cc99f0d0d2f1419894